Midget White hens not laying

I have two Midget White hens who were laying 1-2 eggs between them pretty consistently this winter, and now for the past two months have stopped altogether. I've reconfigured their coop recently to give them more room, and have added a nesting box, which they don't seem interested in using. I keep the tom separate from them most days because he tears up their backs pretty badly, but periodically let them together so he breed them. I'm feeding a game bird feed, put vitamin supplements in their water, and they have free choice ground oyster shell. These birds are three years old, and have successfully hatched out poults prior, but I just got them this past November. They did moult back in March/April - it just seems like they're off seasonally. Any thoughts on how to get them back on track? Is there anything I'm not doing that I should be? Right now they're confined to a 6x6 coop with a 4x5 outdoor area. I have three two-month old poults we got from a hatchery in with them right now as well.

They are done laying would be my guess. My MW's are all sitting on eggs right now, they all went broody on me and they laid most of the winter. My Blue Slates and Royal Palms are still laying but they started about 2 months later.
I dont think you are doing anything wrong. I would look into getting them saddles so the Tom isn't tearing their skin. I think most heritage breeds only lay about 80 eggs a year.